Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Simple Pendulum Problem

  1. Jan 27, 2010 #1
    1. The problem statement, all variables and given/known data

    I searched and got nothing, I am also new here as my friend recently introduced me to this forum last night. I have gotten every single problem correct except this one so here goes:

    A 300 g mass on a 1.0 m long string is pulled 8.8° to one side and released. How long does it take for the pendulum to reach 4.4° on the opposite side?

    I only have one more try or else i lose all my credit (webassign ah) but any help is appreciated. Thank you!

    2. Relevant equations

    T = 2*pi*sqrt(L/g)
    3T/4 = answer

    3. The attempt at a solution

    T= 2*pi*sqrt(1.0/9.81)
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jan 27, 2010 #2
    Why do you say 3T/4 is the answer? From a rational standpoint, it will take less than T/2 to get to 4.4 degrees - its halfway point - since its average speed is greater than going from 4.4 to 8.8 degrees...it will take T/4 to get to equilibrium from its initial position., for sure, but from there you can't use ratios.
     
  4. Jan 27, 2010 #3
    Yeah I suppose that my submission really doesn't make sense at all. But it was my last problem it's been a long day.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook